Diagnosis of rhabdomyosarcoma

Diagnosing rhabdomyosarcoma usually begins with a visit to your child’s doctor. The doctor will ask you about any symptoms your child has and do a physical exam. Based on this information, the doctor may refer you to a specialist or order tests to check for rhabdomyosarcoma or other health problems.

The process of diagnosis may seem long and frustrating. It’s normal to worry, but try to remember that other health conditions can cause similar symptoms as rhabdomyosarcoma. It’s important for the healthcare team to rule out other reasons for a health problem before making a diagnosis of rhabdomyosarcoma.

The following tests are commonly used to diagnose or rule out rhabdomyosarcoma. Many of the same tests used to diagnose cancer are used to find out the stage, which is how far the cancer has progressed. The doctor may also order other tests to check the child’s general health and to help plan treatment.

Health history and physical exam

A health history is a record of the symptoms, risk factors and all the medical events and problems your child has had in the past. In taking a health history, the doctor will ask questions about a personal or family history of certain genetic conditions, including:

Li-Fraumeni syndrome

neurofibromatosis type 1 (von Recklinghausen disease)

Beckwith-Wiedemann syndrome

Costello syndrome

Noonan syndrome

A physical exam allows the doctor to look for any signs of rhabdomyosarcoma. The doctor will do a physical exam and:

check for any swelling or lumps

look at and feel any lumps to check their size and to see if they move or are attached to tissues under the skin, such as muscle or bone

Complete blood count (CBC)

A CBC measures the number and quality of white blood cells, red blood cells and platelets. A CBC is done to check if the cancer has spread to the bone marrow. It is also used as a baseline that doctors can check against during treatment.

Blood chemistry tests

Blood chemistry tests measure certain chemicals in the blood. They show how well certain organs are functioning and can help find abnormalities. Blood chemistry tests can also be used as a baseline that doctors can check against during treatment.

X-ray

An x-ray uses small doses of radiation to make an image of the body’s structures on film. A chest x-ray is sometimes done to see if cancer has spread to the lungs. If a CT scan of the chest is done, doctors won’t do a chest x-ray as well.

CT scan

A computed tomography (CT) scan uses special x-ray equipment to make 3-D and cross-sectional images of organs, tissues, bones and blood vessels inside the body. A computer turns the images into detailed pictures.

Doctors use a CT scan for tumours in the thorax, abdomen, pelvis and the space between the peritoneum and the abdominal wall (called the retroperitoneum). It is used to:

find out how large the tumour is

find out if the tumour has grown into nearby structures

check if cancer has spread to lymph nodes around the tumour

check if cancer has spread to other organs or tissues, such as the lungs

Ultrasound

An ultrasound uses high-frequency sound waves to make images of structures in the body. It is used to look at the kidneys and structures around them. Doctors may also use ultrasound to look at tumours in the pelvis, including in the bladder, prostate, testicles, gallbladder, bile ducts and kidneys.

PET scan

A positron emission tomography (PET) scan uses radioactive materials called radiopharmaceuticals to look for changes in the metabolic activity of body tissues. A computer analyzes the radioactive patterns and makes 3-D colour images of the area being scanned.

A PET scan may be used to:

tell rhabdomyosarcoma from a non-cancerous tumour in a muscle

find out if cancer has spread to other areas of the body

A PET scan can be combined with low-resolution CT scans (called PET-CT scan). Newer machines can do PET and CT scans at the same time. PET-CT scan is used to examine the metabolic activity of specific areas in the body.

PET scans may not be available in all cancer treatment centres. Find out more about PET scan.

Biopsy

During a biopsy, the doctor removes tissues or cells from the body so they can be tested in a lab. The report from the lab will confirm whether or not cancer cells are present in the sample.

A biopsy is the only way to make a definite diagnosis of rhabdomyosarcoma. It is usually done after a CT or MRI of the tumour.

Surgical biopsy

The most common type of biopsy done is a surgical, or open, biopsy. During a surgical biopsy, the doctor cuts through the skin and removes a piece of the tumour. The doctor may also remove lymph nodes near the tumour to see if cancer has spread to them. The child is asleep under general anesthesia during the biopsy.

Needle biopsy

If doctors can’t do a surgical biopsy, they may do a needle biopsy. There are 2 types of needle biopsies:

Core needle biopsy uses a needle to remove a small sample of the tumour. If the tumour is deep within the body, the doctor may use ultrasound or CT scan to guide the needle into the tumour. Find out more about core needle biopsy.

Fine needle aspiration (FNA) biopsy uses a thin needle and a syringe to remove a small amount of fluid or cells. FNA works best with tumours that are just under the skin and can be easily reached with the needle. Find out more about FNA.

Bone marrow aspiration and biopsy

Bone marrow aspiration and biopsy removes tissues or cells from the bone marrow so they can be tested in a lab. Doctors use bone marrow aspiration and biopsy to see if cancer has spread to the bone marrow.

Lumbar puncture

A lumbar puncture, or spinal tap, removes a small amount of cerebrospinal fluid (CSF) from the spine. CSF is the fluid that surrounds and helps protect the brain and spinal cord. The CSF fluid removed during a lumbar puncture is examined under a microscope to see if cancer has spread to the central nervous system (CNS). A lumbar puncture may be done if the tumour is near the tissue surrounding the brain and spinal cord (called the meninges).